This invention relates to an electromagnetic counter, more particularly an electromagnetic counter having shock and vibration preventing mechanisms for preventing misoperations when external shocks and vibrations are applied to the counter.
As is well known in the art, an electromagnetic counter generally comprises a plurality of digit wheels, pinions for transmitting the rotation of the digit wheels, a driving member for driving the digit wheels, and an electromagnetic driving device for imparting a driving force to the driving member, and is incorporated into industrial machines and business machines for displaying their number of operations and the number of inputs, Recently, electromagnetic counters are incorporated into automatic vending machines, game machines etc., for counting the number of inserted coins, the number of merchandise sold and the number of games. Different from industrial machines and business machines which are used by specific operators, automatic vending machines and game machines are used by a plurality of not specified persons including wild acting men who often beat or shake the machines. Since electromagnetic counters are precision machines they are liable to misoperate when shocks or vibration are applied. On the otherhand, electromagnetic counters to be incorporated into such automatic machines and game machines are required to be of low price. A low price electromagnetic counter is disclosed in Japanese Utility model laid open publication No. 71451/1977 in which a portion of the counter frame is used as the yoke of the electromagnetic driving device and the armature comprising a portion of the electromagnetic driving device is formed integral with a driving member for the digit wheels for the purpose of decreasing the cost. However in this electromagnetic counter, the force of an armature spring which urges the pawl of the driving member into engagement with the gears of the digit wheels is divided into two directions with respect to the direction of operation of the armature so that when an external shock or vibration is applied, the driving member integral with the armature tends to operate readily. Inadvertent operation of the driving member results in unwanted driving of the digit wheels thus causing the electromagnetic counter to misoperate. For this reason, in this electromagnetic counter there is provided a member for resiliently supporting a star wheel integrally constructed with the digit wheel. With this construction, however, since the driving member is not held directly it is difficult to prevent misoperation. Moreover, under normal counting operations the driving member imposes a load on means for driving the star wheel.